Biopsy apparatus having integrated thumbwheel mechanism for manual rotation of biopsy cannula

ABSTRACT

A biopsy apparatus includes a driver assembly and biopsy probe mechanism drivably coupled to the driver assembly. The biopsy probe mechanism includes a biopsy cannula having a cylindrical side wall that defines a lumen and has a side port located near a distal end that extends through the side wall to the lumen. A thumbwheel mechanism includes a thumbwheel mounted to the driver assembly to rotate about a first rotational axis, the first rotational axis being substantially perpendicular to the longitudinal axis. A first gear is mounted to the thumbwheel for coaxial rotation with the thumbwheel about the first rotational axis. A second gear is mounted to the biopsy cannula for coaxial rotation with the biopsy cannula about the longitudinal axis, the second gear being located to be drivably engaged by the first gear. The housing is grasped and the thumbwheel rotated with a single hand.

CROSS REFERENCE TO RELATED APPLICATIONS

None.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a biopsy apparatus, and, more particularly, to a biopsy apparatus having an integrated thumbwheel mechanism for manual rotation of a biopsy cannula.

2. Description of the Related Art

A biopsy may be performed on a patient to help in determining whether the cells in a biopsied region are cancerous. One biopsy technique used to evaluate breast tissue, for example, involves inserting a biopsy probe into the breast tissue region of interest to capture one or more tissue samples from the region. Such a biopsy technique often utilizes a vacuum to pull the tissue to be sampled into a sample notch of the biopsy probe, after which the tissue is severed and collected. One type of vacuum assisted biopsy apparatus includes a hand-held driver assembly having a vacuum source, and a disposable biopsy probe assembly configured for releasable attachment to the driver assembly. The biopsy probe typically includes a biopsy cannula, e.g., a needle, having a side port for receiving the tissue to be sampled.

During a biopsy procedure, it may be desirable to position the side port to various angular positions around a longitudinal axis of the biopsy cannula without having to rotate the hand-held driver assembly. One console-type biopsy device includes a control console tethered to a hand-held driver assembly, wherein the control module is programmed to provide automatic indexing of the side port to predetermined angular positions. However, such automatic indexing may limit the ability of the physician to make real-time changes and/or minute changes to the angular position of the side port.

Also, it is known to provide manual indexing of the side port of the biopsy cannula by attaching a knob to the distal end of the biopsy cannula, and then simply rotate the knob to position the side port to the desired angular position. One disadvantage, however, is that such an arrangement requires the physician to hold the handle of the hand-held driver assembly in one hand, while rotating the knob with the other hand.

SUMMARY OF THE INVENTION

The present invention provides a biopsy apparatus having a mechanism that enables a user to operate the biopsy apparatus and manually rotate a side port of a biopsy cannula to a desired rotational position about the longitudinal axis relative to the driver assembly through a single-handed operation of the biopsy apparatus. Mechanisms may also provide at least one of tactile, aural and visual feedback of the rotation of the biopsy cannula, as well as facilitate the selective locking of the biopsy cannula from further rotation so as to maintain a current rotational position of the side port of the biopsy cannula during the harvesting of a tissue sample.

As used herein, the terms “first” and “second” preceding an element name, e.g., first gear, second gear, etc., are for identification purposes to distinguish between different elements having similar characteristic, and are not intended to necessarily imply order, unless otherwise specified, nor are the terms “first” and “second” intended to preclude the inclusion of additional similar elements.

The invention in one form is directed to a biopsy apparatus. The biopsy apparatus includes a driver assembly having a housing configured to be grasped by a user. A biopsy probe mechanism is drivably coupled to the driver assembly. The biopsy probe mechanism includes a biopsy cannula having a cylindrical side wall, a proximal end, a distal end and a longitudinal axis extending between the proximal end and the distal end. The cylindrical side wall defines a lumen and has a side port located near the distal end that extends through the side wall to the lumen. A thumbwheel mechanism includes a thumbwheel mounted to the driver assembly to rotate about a first rotational axis, the first rotational axis being substantially perpendicular to the longitudinal axis, wherein at least a portion of the thumbwheel is exposed external to the housing. A first gear is mounted to the thumbwheel for coaxial rotation with the thumbwheel about the first rotational axis. A second gear is mounted to the biopsy cannula for coaxial rotation with the biopsy cannula about the longitudinal axis, the second gear being located to be drivably engaged by the first gear. A user grasps the housing and rotates the thumbwheel with a single hand to rotatably position the side port of the biopsy cannula at a desired rotational position about the longitudinal axis relative to the driver assembly.

The invention in another form is directed to a biopsy apparatus. The biopsy apparatus includes a driver assembly having a housing configured to be grasped by a user. A disposable biopsy probe mechanism is configured for releasable attachment to the driver assembly. The disposable biopsy probe mechanism is positioned at least partially within the housing when the disposable biopsy probe mechanism is attached to the driver assembly. The disposable biopsy probe mechanism includes a biopsy cannula having a cylindrical side wall, a proximal end, a distal end and a longitudinal axis extending between the proximal end and the distal end. The cylindrical side wall defines a lumen and has a side port located near the distal end that extends through the side wall to the lumen. The driver assembly includes a thumbwheel and a first gear, the thumbwheel and the first gear being coupled for unitary coaxial rotation about a first rotational axis. The first rotational axis is substantially perpendicular to the longitudinal axis. At least a portion of the thumbwheel is exposed external to the housing. The biopsy cannula includes a second gear configured for unitary coaxial rotation with the biopsy cannula about the longitudinal axis. The second gear is positioned to be drivably engaged by the first gear when the biopsy probe mechanism is attached to the driver assembly. A user rotates the thumbwheel while grasping the housing to effect a manual rotation of the biopsy cannula to position the side port of the biopsy cannula at a desired rotational position about the longitudinal axis relative to the driver assembly.

The invention in another form thereof is directed to a biopsy apparatus. The biopsy apparatus includes a driver assembly having a housing configured to be grasped by a user. A biopsy probe mechanism is drivably coupled to the driver assembly. The biopsy probe mechanism includes a biopsy cannula having a cylindrical side wall, a proximal end, a distal end and a longitudinal axis extending between the proximal end and the distal end. The cylindrical side wall defines a lumen and having a side port located near the distal end that extends through the side wall to the lumen. A thumbwheel mechanism is interposed between the driver assembly and the biopsy probe mechanism. The thumbwheel mechanism includes a thumbwheel drivably coupled to the biopsy cannula to rotatably position the side port of the biopsy cannula at a desired rotational position about the longitudinal axis relative to the driver assembly. A detent wheel is mounted to the biopsy cannula for coaxial rotation with the biopsy cannula about the longitudinal axis. The detent wheel has a circumferential surface and a plurality of detent recesses formed through the circumferential surface that extends radially toward the longitudinal axis. The plurality of detent recesses are positioned about the longitudinal axis at predetermined angular positions. An engagement device has an engagement element biased in constant engagement with the detent wheel, wherein as the biopsy cannula is rotated the engagement element rides along the circumferential surface of the detent wheel and produces at least one of a tactile and an aural feedback each time the engagement element engages one of the plurality of detent recesses.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side view of a biopsy apparatus configured in accordance with an embodiment of the present invention, with a biopsy probe mechanism mounted to a driver assembly, and with a side portion broken away to expose internal components which are schematically represented in part;

FIG. 2 is a section view of a biopsy cannula of the biopsy apparatus of FIG. 1, taken along line 2-2 of FIG. 1;

FIG. 3 is a perspective view of the thumbwheel mechanism of the biopsy apparatus of FIG. 1, which includes positioning and locking mechanisms;

FIG. 4 is rear view of the thumbwheel mechanism of FIG. 3;

FIG. 5 is a section view of the biopsy cannula coupled to the detent wheel of the positioning mechanism of FIG. 3, taken along line 5-5 of FIG. 3;

FIG. 6A is a side view of a portion of the locking mechanism of FIGS. 3 and 4 with the locking pin in the unlocked rotational position; and

FIG. 6B is a side view of a portion of the locking mechanism of FIGS. 3 and 4 with the locking pin in the locking rotational position.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate an embodiment of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIG. 1, there is shown a biopsy apparatus 10 which generally includes a driver assembly 12 and a biopsy probe mechanism 14.

Driver assembly 12 is configured to provide operative control over biopsy probe mechanism 14. Driver assembly 12 may be, for example, a non-disposable device, or alternatively a disposable device. As used herein, the term “non-disposable” is used to refer to a device that is intended for use on multiple patients during the lifetime of the device. Also, as used herein, the term “disposable” is used to refer to a device that is intended to be disposed of after use on a single patient.

Accordingly, in some embodiments driver assembly 12 and biopsy probe mechanism 14 may be releasably attached to one another. In other embodiments, however, it is contemplated that driver assembly 12 and biopsy probe mechanism 14 may be permanently attached to each other to form an integral biopsy apparatus, such that the entire biopsy apparatus is made to be disposable.

Driver assembly 12 includes a housing 16 configured, e.g., ergonomically designed, to be grasped by a user, e.g., a physician. Housing 16 defines a compartment 18 into which biopsy probe mechanism 14 is at least partially positioned when biopsy probe mechanism 14 is attached to driver assembly 12, with biopsy probe mechanism 14 being drivably coupled to driver assembly 12.

Biopsy probe mechanism 14 is generally intended to be disposable as a unit. In the present embodiment, biopsy probe mechanism 14 is configured for releasable attachment to driver assembly 12. As used herein, the term “releasable attachment” means a configuration that facilitates an intended temporary connection followed by selective detachment involving a manipulation of disposable biopsy probe mechanism 14 relative to driver assembly 12, e.g., without the need for tools. Biopsy probe mechanism 14 includes a frame 19 to which a biopsy cannula 20 and a cutting cannula 22 are mounted. Biopsy cannula 20 and a cutting cannula 22 are arranged coaxially with respect to a longitudinal axis 24.

Cutting cannula 22 has a distal cutting end 26.

Referring to FIGS. 1 and 2, biopsy cannula 20 has a cylindrical side wall 28 having a proximal end 30 and a distal end 32, wherein the longitudinal axis 24 extends between the proximal end 30 and the distal end 32. Cylindrical side wall 28 defines a lumen 34 and has a side port 36 located near distal end 32. Side port 36 extends through the side wall to the lumen 34 to a portion of the lumen 34 referred to as the sample chamber, or basket, 38. Biopsy cannula 20 may, for example, be in the form of a hollow needle having a piercing tip 40.

Driver assembly 12 further includes a user interface 42 located to be externally accessible to the user with respect to housing 16 for receiving operation commands from the user, e.g., through one or more pushbuttons, and may also include a display, e.g., one or more lights or an LCD (liquid crystal display), to display information to the user. A controller 44 is communicatively coupled user interface 42. Controller 44 may include, for example, a microprocessor and associated memory (not shown) for executing program instructions to perform functions associated with the harvesting of biopsy tissue samples during a biopsy procedure.

There is contained within housing 16 an electromechanical drive 46 and a vacuum source 48. Electromechanical drive 46 is connected in electrical communication with controller 44. Electromechanical drive 46 is further drivably coupled (illustrated by dashed lines) to the biopsy probe mechanism 14 and to the vacuum source 48 to selectively and operatively control vacuum source 48 and/or cutting cannula 22. Electromechanical drive 46 may include, for example, one or more of a linear drive that converts rotational motion to linear motion (e.g., a worm gear arrangement, rack and pinion arrangement, solenoid-slide arrangement, etc.) and a rotational drive that may include one or more of a gear, gear train, belt/pulley arrangement, etc., for effecting operation of cutting cannula 22 of biopsy probe mechanism 14 and/or vacuum source 48.

Vacuum source 48 may be, for example, a peristaltic pump, a diaphragm pump, syringe-type pump, etc. Vacuum source 48 may be permanently integrated into driver assembly 12, or alternatively may be permanently integrated as a part of the biopsy probe mechanism 14. In either case, vacuum source 48 is coupled in fluid communication with lumen 34 of biopsy cannula 20.

During a biopsy procedure, for example, biopsy cannula 20 and cutting cannula 22 are relatively positioned such that side port 36 is closed by cutting cannula 22. Biopsy cannula 20 and cutting cannula 22 are advanced into the tissue region to be sampled of a patient. Commands are sent via user interface 42 to electromechanical drive 46 to open side port 36 by retracting cutting cannula 22 along longitudinal axis 24, and to operate vacuum source 48 so as to selectively draw tissue though side port 36 of biopsy cannula 20 into sample chamber 38. Once tissue is received through side port 36, electromechanical drive 46 is controlled to cause cutting cannula 22 to advance linearly along longitudinal axis 24 to close side port 36 and sever the tissue prolapsed into sample chamber 38. In some circumstances, it may be desirable for electromechanical drive 46 to cause cutting cannula 22 to rotate or oscillate during the linear advancement. The severed tissue may then be advanced to a tissue collection receptacle 49, such as for example by vacuum, where the tissue samples may be retrieved. Alternatively, in an embodiment wherein vacuum source 48 is in direct fluid communication with lumen 34 (i.e., to the exclusion of tissue collection receptacle 49), each of the tissue samples may simply be retained in lumen 34 of biopsy cannula 20.

Referring also to FIGS. 3-5, further convenience may be provided to the user by the inclusion of a thumbwheel mechanism 50 interposed between driver assembly 12 and biopsy probe mechanism 14 to facilitate a manual rotation of biopsy cannula 20 relative to driver assembly 12. The rotation of biopsy cannula 20 may be in either the clockwise or counterclockwise directions, as indicated by double-headed arrow 51. More particularly, a user may grasp housing 16 of driver assembly 12 with a single hand and may operate thumbwheel mechanism 50 with a thumb or finger of the same hand to rotatably position side port 36 of biopsy cannula 20 at a desired rotational position, e.g. rotational position 52, about longitudinal axis 24 relative to driver assembly 12, wherein the desired rotational position 52 is an angular value, e.g., 30 degrees in the present example, in a range of angular values from 0 degrees to 360 degrees, inclusive, as illustrated in FIG. 5.

As best shown in FIGS. 3 and 4, thumbwheel mechanism 50 includes a thumbwheel 54, a first gear 56 and a second gear 58. Each of first gear 56 and second gear 58 may be, for example, a bevel gear.

Thumbwheel 54 and first gear 56 is rotatably mounted to driver assembly 12 by an axle/bearings arrangement 60, including bearings 60-1, 60-2 and axle 60-3, to rotate about a first rotational axis 62. The unit formed by thumbwheel 54, first gear 56 and axle/bearing arrangement 60 may be mounted to housing 16 of driver assembly 12 via a mounting plate 61 and a pair of screws 63. First rotational axis 62 is positioned to be substantially perpendicular to longitudinal axis 24. As shown in FIGS. 1 and 4, at least a portion 55 of thumbwheel 54 is exposed external to housing 16 of driver assembly 12.

First gear 56 is coupled, e.g., mounted in fixed attachment, to thumbwheel 54 for unitary coaxial rotation with thumbwheel 54 about first rotational axis 62. Second gear 58 is coupled, e.g., mounted in fixed attachment, to biopsy cannula 20 for unitary coaxial rotation with biopsy cannula 20 about longitudinal axis 24. As shown, second gear 58, and in turn biopsy probe mechanism 14, is located to be drivably engaged by first gear 56 when said biopsy probe mechanism 14 is attached to driver assembly 12.

Accordingly, the user grasps housing 16 and rotates thumbwheel 54 with a single hand to effect a manual rotation of biopsy cannula 20 to thereby rotatably position side port 36 of biopsy cannula 20 at a desired rotational position, e.g., rotational position 52, about longitudinal axis 24 relative to driver assembly 12 in a range of 0 degrees through 360 degree, as illustrated in FIG. 5. Thumbwheel 54 may include an indicia, e.g., “UP”, located on the periphery of thumbwheel 54 to coincide with the designated “up” position, i.e., the 0/360 degree position of side port 36 (see FIG. 5). As also shown in FIG. 3, other indicia, such as “LT” for left and “RT” for right, may be included to aid in indicating the rotational direction of biopsy cannula 20.

Thumbwheel mechanism 50 may further include a positioning mechanism 64 coupled to said biopsy cannula 20 to provide resistive positioning of side port 36 of biopsy cannula 20 at discrete angular positions about longitudinal axis 24, and may further provide at least one of tactile and aural feedback to the user as biopsy cannula 20 is rotated about longitudinal axis 24 relative to driver assembly 12.

Referring to FIGS. 3-5, positioning mechanism 64 includes a detent wheel 66, an engagement device 68, and a lock mechanism 70. While the present embodiment includes both engagement device 68 and lock mechanism 70, it is contemplated that alternatively it may be desirable to have only one of engagement device 68 and lock mechanism 70 without the other. In such an alternative, one of engagement device 68 and lock mechanism 70 would simply be deleted from the design.

Detent wheel 66 is mounted to biopsy cannula 20 for unitary coaxial rotation with biopsy cannula 20 about longitudinal axis 24. Detent wheel 66 has a circumferential surface 72 and a plurality of detent recesses 74-1, 74-1 . . . 74-N formed through circumferential surface 72 and extending radially toward longitudinal axis 24, wherein “N” is the total number of detents and is a positive integer. Each of the plurality of detent recesses 74-1 through 74-N may be formed, for example, as a cup-shaped void having a tapered side wall that is curved or a frustoconical.

The plurality of detent recesses 74-1 through 74-N are positioned about longitudinal axis 24 at predetermined angular positions, as illustrated in FIG. 5. In the present exemplary embodiment, the plurality of detent recesses 74-1 through 74-N are arranged in uniform angular increments of 30 degrees, and thus the number of detents is N=12. However, for more coarse angular increments N may be less than 12 and for finer (more minute) angular increments N may be greater than 12, as desired.

Engagement device 68 is mounted to biopsy probe mechanism 14, such as to frame 19. Engagement device 68 includes an engagement element 76 biased by a spring 78 to be in constant engagement with detent wheel 66. Engagement element 76 may be, for example a metallic ball or plug having a rounded or tapered end. Spring 78 may be, for example a coil spring, leaf spring, etc. Thus, as biopsy cannula 20 is rotated, engagement element 76 rides along circumferential surface 72 of detent wheel 66 and produces a resistive positioning of biopsy cannula 20, which is experienced by the user as a tactile interruption and/or aural feedback (e.g., a click sound) each time engagement element 76 engages one of the plurality of detent recesses 74-1 through 74-N of detent wheel 66.

Also, in some biopsy applications as illustrated in FIG. 5, the plurality of detent recesses 74-1 through 74-N may be positioned about longitudinal axis 24 at uniform angular increments and be of a sufficient population N such that an opening defined by side port 36 at a current position (e.g., 74-1) will overlap with the opening of side port 36 at a next position (e.g., 74-2) at each of the angular increments, whereby providing a full 360 degrees of sampling capability.

In general, lock mechanism 70 includes a locking pin 80 having a proximal end 82 and an engagement end 84, and is longitudinally arranged along a locking axis 86. A head portion 88 is attached, or formed integral with, the proximal end 82 of locking pin 80. A shaft portion 90 extends from head portion 88 toward engagement end 84. A spring 91 biases locking pin 80 along locking axis 86 toward detent wheel 66.

Thus, locking pin 80 is configured for linear movement along locking axis 86 relative to circumferential surface 72 of detent wheel 66 for selective locking engagement of engagement end 84 with one of the plurality of detent recesses 74-1 through 74-N of detent wheel 66 to prevent a rotation of biopsy cannula 20 from a current angular position of side port 36 of biopsy cannula 20 relative to driver assembly 12.

Referring also to FIGS. 6A and 6B, engagement end 84 of locking pin 80 may have a tapered portion 92 and a non-tapered portion 94 angularly offset, e.g., at 90 degrees, from tapered portion 92 about locking axis 86. In the present embodiment, tapered portion 92 may have a curved or beveled faces 95 that smoothly transitions to the tip end 96 of engagement end 84, and the non-tapered portion 94 may have a straight faces 97 that abruptly transition, e.g., at 90 degrees, to the tip end 96 of engagement end 84.

In operation, for example, when locking pin 80 is positioned in an unlocked rotational position 98 relative to locking axis 86 and detent wheel 66, as illustrated in FIG. 6A, engagement end 84 rides along circumferential surface 72 of detent wheel 66 and tapered portion 92 sequentially passes into and out of a respective detent recess of the plurality of detent recesses 74-1 through 74-N of detent wheel 66 (see also FIGS. 3-5) as biopsy cannula 20 is rotated, thereby operating similarly to engagement device 68 in providing a positioning mechanism that provides at least one of aural, visual and tactile feedback of a progressive rotation of biopsy cannula 20.

However, when locking pin 80 is positioned in a locking rotational position 100 relative to locking axis 86 and detent wheel 66, as illustrated in FIG. 6B, as biopsy cannula 20 is rotated engagement end 84 rides along circumferential surface 72 of detent wheel 66 and non-tapered portion 94 lockably engages a next encountered detent recess of the plurality of detent recesses 74-1 through 74-N of detent wheel 66 (see also FIGS. 3-5) to lock biopsy cannula 20 from further rotation. Locking pin 80 is released from locking rotational position 100 by a further 90 degree rotation of locking pin 80 relative to locking axis 86, in either rotational direction, to unlocked rotational position 98.

While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. 

1-12. (canceled)
 13. A biopsy apparatus, comprising: a driver assembly having a housing configured to be grasped by a user; a biopsy probe mechanism drivably coupled to said driver assembly, said biopsy probe mechanism including a biopsy cannula having a cylindrical side wall, a proximal end, a distal end, and a longitudinal axis extending between said proximal end and said distal end, said cylindrical side wall defining a lumen and having a side port located near said distal end that extends through said side wall to said lumen; and a thumbwheel mechanism interposed between the driver assembly and the biopsy probe mechanism, said thumbwheel mechanism including: a thumbwheel drivably coupled to said biopsy cannula and configured to rotatably position said side port of said biopsy cannula at a desired rotational position about said longitudinal axis relative to said driver assembly; a detent wheel mounted to said biopsy cannula configured for coaxial rotation with said biopsy cannula about said longitudinal axis, said detent wheel having a circumferential surface and a plurality of detent recesses formed through said circumferential surface and extending radially toward said longitudinal axis, said plurality of detent recesses being positioned about said longitudinal axis at a set of predetermined angular positions; and an engagement device having an engagement element biased in constant engagement with said detent wheel, and configured such that as said biopsy cannula is rotated said engagement element rides along said circumferential surface of said detent wheel and produces at least one of a tactile and an aural feedback each time said engagement element engages one of said plurality of detent recesses.
 14. The biopsy apparatus of claim 13, wherein said plurality of detent recesses being positioned about said longitudinal axis at said set of predetermined angular positions, wherein an opening defined by said side port at a current position will overlap with the opening at a next position at each of said set of predetermined angular positions.
 15. The biopsy apparatus of claim 13, further comprising a lock mechanism having a locking pin that is configured for linear movement relative to said circumferential surface for selective locking engagement with one of said plurality of detent recesses of said detent wheel to prevent a rotation of said biopsy cannula from a current angular position of said side port of said biopsy cannula relative to said driver assembly.
 16. The biopsy apparatus of claim 15, said locking pin including an engagement end having a tapered portion and a non-tapered portion angularly offset from said tapered portion about a locking axis, configured such that when said locking pin is positioned in a first rotational position relative to said locking axis, said engagement end rides along said circumferential surface of said detent wheel and said tapered portion sequentially passes into and out of a respective detent recess of said plurality of detent recesses of said detent wheel as said biopsy cannula is rotated thereby providing at least one of aural, visual and tactile feedback of a progressive rotation of said biopsy cannula, and configured such that when said locking pin is positioned in a second rotational position relative to said locking axis, said engagement end rides along said circumferential surface of said detent wheel and said non-tapered portion lockably engages a next detent recess of said plurality of detent recesses of said detent wheel as said biopsy cannula is rotated to lock said biopsy cannula from further rotation.
 17. The biopsy apparatus of claim 13, configured such that the user can both grasp said housing and manually rotate said thumbwheel with a single hand to rotatably position said side port of said biopsy cannula at a desired rotational position about said longitudinal axis relative to said driver assembly.
 18. A biopsy apparatus, comprising: a housing; a biopsy cannula mounted to the housing, the biopsy cannula having a cylindrical side wall, a proximal end, a distal end, and a longitudinal axis extending between the proximal end and the distal end, the cylindrical side wall defining a lumen and having a side port located near the distal end that extends through the side wall to the lumen; a thumbwheel configured to rotate about a first rotational axis, the first rotational axis being perpendicular to the longitudinal axis, the thumbwheel being located such that only a portion of the thumbwheel is exposed external to the housing; a first gear mounted in fixed attachment to the thumbwheel and configured for coaxial rotation with the thumbwheel about the first rotational axis; and a second gear mounted in fixed attachment to the biopsy cannula and configured for coaxial rotation with the biopsy cannula about the longitudinal axis, the first gear mounted in fixed attachment to the thumbwheel and the second gear mounted in fixed attachment to the biopsy cannula being oriented such that the first gear is directly drivably engaged with the second gear.
 19. The biopsy apparatus of claim 18, configured such that the user can both grasp the housing and manually rotate the thumbwheel with a single hand to rotatably position the side port of the biopsy cannula at a desired rotational position about the longitudinal axis relative to a driver assembly.
 20. The biopsy apparatus of claim 18, further comprising: a detent wheel mounted to the biopsy cannula configured for coaxial rotation with the biopsy cannula about the longitudinal axis, the detent wheel having a circumferential surface and a plurality of detent recesses formed through the circumferential surface and extending radially toward the longitudinal axis, the plurality of detent recesses being positioned about the longitudinal axis at a set of predetermined angular positions; and an engagement device having an engagement element biased by a spring to be in constant engagement with the detent wheel, and configured such that as the biopsy cannula is rotated the engagement element rides along the circumferential surface of the detent wheel and produces at least one of a tactile and an aural feedback each time the engagement element engages one of the plurality of detent recesses.
 21. The biopsy apparatus of claim 20, wherein the plurality of detent recesses are positioned about the longitudinal axis at the set of predetermined angular positions, wherein an opening defined by the side port at a current position will overlap with the opening at a next position at each of the set of predetermined angular positions.
 22. The biopsy apparatus of claim 20, wherein the engagement element has a tapered end. 